Free Float
Scheduling Terms
Reviewed by forProject Technology - updated Sep 2026
Quick definition: Free Float (also called Free Slack) is the amount of time a task can be delayed without delaying the early start of its immediately following (successor) tasks.
Free Float is the gap between a task's Early Finish and the earliest Early Start of its successors, measured on the Working Calendar. If the task has no successors, the project finish date is used instead. It's more conservative than Total Float, since it looks only at the next tasks rather than the whole remaining path. Microsoft Project calls it Free Slack; Primavera P6 and some other scheduling tools call it Free Float.
What this means for you
Free Float tells a scheduler how much a task can slip without creating any ripple effect on the next task at all. That's useful for avoiding disruption to other teams' start dates, even when the overall project finish date has more cushion available through Total Float.
Also known as
Free Slack
Used in
Critical Path Method scheduling
FAQ
How is Free Float different from Total Float?
Free Float measures how long a task can slip before it delays any Successor task, while Total Float measures how long it can slip before it delays the project finish. Free Float is always less than or equal to Total Float.
What happens if a task has no successor tasks?
Its Free Float is calculated against the project finish date instead of a successor's start date.
Definition maintained by forProject Technology.
© 2026 forProject Technology, Inc.
© 2026 forProject Technology, Inc.
